Carbureting device



Dec. 12, 1950 M. L. MENNESSON CARBURETING DEVICE Filed Feb. 27, 1946 AVII/14,1!!! Ill 7 INVENTOR MA RCEL Louis MENNESSON TOR NEY Patented Dec.12, 1950 CARBURETING DEVICE Marcel Louis Mennesson,

Neuilly-sur-Seine,

France, assignor to Societe Solex, a society of the Republic of FranceApplication February 2'7, 1946, Serial No. 650,517 In France February 8,1945 Section 1, Public Law 690, August 8, 1946 Patent expires February8, 1965 2 Claims.

The present invention relates to carburetting devices including anauxiliary carburetter for facilitating the starting from cold ofinternal:

combustion. engines, said auxiliary carburetter being of the kind ofthose described in French Patents No. 700,188 and 751.064, filed bySocit Anonyme Solex. Such auxiliary carburetters essentially include awell communicating through a calibrated orifice with the constant levelchamber below the fuel level, and fed with air at its upper part, thefuel mixture thus obtained being mixed with air, and the whole beingfed, through a passage controlled by a cock, to the engine intake pipeon the downstream side of its throttle valve.

The chief object of my invention is to provide a device of this kindwhich is better adapted to meet the requirements of practice than thosemade up to this time, in particular concerning the feed of air to theair intakes of the auxiliary carburetter and the fluidtightness of thecock that serves to bring the auxiliary carburetter into or out ofaction and to adjust the section of the passage through which the fuelmixture is fed to the engine intake.

According to a feature of the present invention, the air intakes inquestion and in particular the upper end of the well are connected, notwith the atmosphere but with the. space of the constant level chamberabove the fuel, said space being itself connected, through an orifice oflarge section, with the main air inlet-generally fitted with a purifieror filter-of the main carburetter, so that the air intakes of theauxiliary carburetter are fed through the air intake of the maincarburetter and any slight depression as may be produced in the well ofthe auxiliary carburetter, when the latter is brought into play, remainspractically without influence on the pressure existing in the constantlevel chamber.

According to another feature of the present invention, there isprovided, between the parts of the channel for the feed of the fuelmixture from the auxiliary carburetter that are respectively located onthe upstream side and the downstream side of the above mentioned cock, achamber in communication either with the atmosphere, or with the airintake of the main carburetter or again with the constant level chamberabove the normal fuel level therein, in order to prevent the depression,existing in the downstream part, from being transmitted to the upstreampart due to a lack of fluidtightness of said cock.

Fig. 1 shows, in diagrammatic axial section, a

carburetting device made according to the invention; Fig. 2 shows, in asimilar way, a portion of the same device, but with parts thereofoccupying another position;

Fig. 3 is a view, similar to Fig. 2, showing a modification.

The main carburetter is constituted in any suitable manner, inparticular as usual. Fig. 1

' shows, by way of example, only some essential elements of an invertedtype carburetter, i. e. a body I, an air intake 2 (generally providedwith a purifier or filter), a venturi 3, a jet device 4 (shown inexternal view), a throttle valve or butterfly valve 5, and a constantlevel chamber 6 with its float I.

Concerning the auxiliary carburetter it is essentially constituted, asindicated in French Patents No. 700,188 and 738,525 filed by SocitAnonyme Solex. In the example illustrated by the drawings, it includes awell 9 fed with fuel, at its lower part, through a calibrated orifice l0opening into the constant level chamber 6 below the fuel level therein.A conduit ll starting from a point of well 9 located at a given distancebelow the fuel level leads,,through a channel I2, to a distributingdevice including a chamber l3 and a plate or disc M, of generallycircular shape, adapted to be rotated by means of a spindle l5 and aneternal control member i6. Said plate is applied on its seat,constituted for instance by a plane portion of the body I of thecarburetter, by a spring l1 so as to form a fluidtight partition betweenchannel l2 and chamber l3 when the cock is closed (Fig. 2).

When the cock is open (Fig. 1) for bringing the auxiliary carburetterinto action, an orifice l8 provided in plate I4, is in registry with theopening of channel [2 and permits the contents thereof to pass intochamber 13. At the same time another orifice IQ of plate I4 comesopposite a passage 20 opening into the intake pipe of the engine, on thedownstream side of throttle valve 5, and therefore in directcommunication with the engine. Chamber I3 is permanently connected,through calibrated orifice 22, with a conduit 2| which communicates at23 with the air intake 2 of the main carburetter. Under these conditionsthe depression from the engine is transmitted to chamber I 3 throughpassage 20 and sucks in, on the one hand the air supplied throughconduit 2|, and calibrated orifice 22 and, on the other hand, the fuelmixture delivered through channel l2 and conduit II from well 9.

In the above mentioned prior patents, the upper part of-well 9 wasconnected directly with the atmosphere or with the air intake of themain carburetter.

According to the present invention, the upper part of the wellcommunicates, at 24, with the constant level chamber 6above the normallevel of the fuel contained in this chamber-and, consequently, with theair intake of the main carburetter through orifice 8.

As the transverse section of well 9 is large in comparison with that ofconduit ll, calibrated orifice I is subjected but to a small portion ofthe depression that exists in said conduit I I, and its output issubstantially constant. It follows that the fuel mixture becomes leanerand leaner as the speed of the engine increases. However, in order tohave an operation that is quite correct, the free surfaces of theliquid, in well 9 and in the constant level chamber must be exactly atth same pressure, otherwise a slight difference of pressure would causethe fuel to rise or to drop in well 9 thus producing pcrturbances thatare often very serious.

The only way to obtain this result is to cause the upper part of well 9to open into the constant level chamber itself, this chamber being incommunication with the main air intake 2 through an orifice 8 ofsufficiently large size. As a matter of fact, if orifice 8 is too small,conduit II creates a. slight depression in constant level chamber 6,which has for its efiect to cause a drop of level in the main jet system4 and to make it difficult for gasoline to spout out from this systemwhen butterfly valve 5 is gradually opened for increasing the power ofthe engine. It is therefore important that the depression existing inconduit II when starting should produce no depression in constant levelchamber 6.

It is therefore necessary to give orifice 8 a sumciently large section.On the other hand conduit II has a portion thereof located at asufiiciently high level for avoiding a constant flow of fuel towardplate I.

When the auxiliary carburetter is started into operation, there mighttake place a siphoning of the fuel through conduit II, channel I2 andorifice i8 when the latter is open or even through an eventual leakbetween plate It and its seat if orifice I8 is not opposite the channelI2. In order to avoid such a siphoning, a hole 25 is provided at the toppoint of conduit II. On the other hand, when the auxiliary carburetteris out of action, orifice I9 is no longer opposite passage 28 andorifice I8 is no longer opposite the opening of channel 20.

It was proposed, in the prior patents above mentioned, to providewhenthe auxiliary carburetter is out of action-a second orifice, analogousto that designated by I3. for causing atmospheric pressure to act inconduit I I. In the case of the device that constitutes the object ofthe present invention, such a hole would connect channel I2 with chamberI3 and, consequently, with the main air intake of the car- Now,

channel I2 and chamber I3. But it may happen, due to a lack of fluidtightness, that the depression from the engine intake pipe istransmitted through passage 20 to channel I2 by passing between plate Idand its seat, which would have for its effect to suck out fuel from well9, this fuel then passing direcly into the suction pipe of the engine.

This is remedied by surrounding the outlet of channel I2 by a groove 26'communicating, for instance, with the outside. With such an arrangement,a slight depression tending to reach channel l2 through the intervalthat may exist between plate M and its seat would first meet with thisgroove 26 and the only inconvenience that might result therefrom wouldbe that the engine would suck in a small amount of air through the leakthus formed.

However, there may also exist a slight lack of fluidtightness betweengroove 26 and channel I2 due to a defective contact between plate It andits seat and, in these conditions, as constant level chamber 6 may be ata pressure lower than atmospheric pressure, air from the outside wouldenter conduit II through channel I2 and groove 26 and bubble in well 8,thus causing perturba-.

tions therein. It is therefore of interest to place groove 26 incommunication through a conduit 27 with the part of constant levelchamber 6 above the normal fuel level therein. In this way no diiTerenceof pressure can occur, when the auxiliary carburettor is out of action(Fig. 2), between channel I2 and groove 25, the latter remaining quiteas efficient for compensating the eliects of a certain suctiontransmitted from passage 20.

Another solution, shown by Fig. 3, consists in placing groove 26 incommunication, through passage 28, with chamber I3. When the auxiliarycarburetter is out of action (Fig. 3) passage 28 communicates directlywith the carburetter air intake through chamber l3, calibrated orifice 5difference of pressure may exist between conduits II and I2 on the onehand, which are at the pressure of constant level chamber 6, and groove26 on the other hand which is at the pressure existing in thecarburettor air intake, at the inlet 23 of conduit 2 I.

This slight difierence of pressure might produce a circulation of fuelthrough conduits 2|, I2 and II, but this can be remedied, as in thepreceding case, by having recourse to a hole 25 (Fig. 1) which permitsan inflow of air into conduits II and I2 preventing fuel from beingsucked up to the top point of conduit II from which it could pass intochannel I2. However the size of hole 25 is chosen such that it does notinterfere with the suction of the fuel when plate I4 occupies a positionfor which the auxiliary carburetter is in action (Fig. 2), that is tosay when the maximum depression exists in conduit II.

Of course, the air that feeds calibrated orifice 22 might also be takenfrom constant level chamber 6 but as this orifice is, on the one handand in general, of rather important dimension and, on the other hand,subjected to a strong suction, this arrangement would lead to an orifice8 of considerable section. It is therefore preferable to have conduit 2iopening, at 23, into the main air intake of the carburetter and not intothe constant level chamber.

In this carburation device, including a starting auxiliary carburettor,all the possible air intakes finally lead to the main air intake of thecarburetter and are, consequently, fed with air filtered by the mainfilter of the carburetter, if such a filter exists, without having tofear that the feeds of these difierent air intakes, including that ofthe constant level chamber, give rise, during the working of the engine,to local pressure differences which might be the cause of disturbancesin the working of the auxiliary carburetter or even in that of theconstant level chamber.

In a general manner, while I have, in the above description, disclosedwhat I deem to be practical and efliclent embodiments of the presentinvention, it should be well understood that I do not wish to be limitedthereto as there might be changes made in the arrangement, dispositionand form of the parts-without departing from the principle of thepresent invention as a main carburetter including an air intake, a

constant level chamber communicating with said air intake through alarge section passage, an induction pipe to be connected with saidengine, and a throttle valve in said pipe, and an auxiliary carburetterfor starting the engine from cold including a well provided with acalibrated orifice opening into said constant level chamber below thefuel level therein and with only one air inlet in direct communicationexclusively with the space of said constant level chamber above the fuellevel therein, a chamber located below said first mentioned chamber, aconduit starting from said well at a point thereof located below thefuel level in said constant level chamber, passing above said level andopening into one wall of said second mentioned chamber, a conduitstarting from said induction pipe on the downstream side of saidthrottle valve and opening into said wall of the last mentioned chamber,a valve member slidable along said wall adapted either to connect bothof said conduits with said last mentioned chamber or to cut off both ofthem therefrom, a conduit provided with a calibrated orifice forconnecting said last mentioned chamber with said air intake, said wallof said last mentioned chamber being provided with an annular groovesurrounding the opening of the first mentioned conduit into said wall,and means for connecting said groove with said second mentioned chamber.

2. A carburation device for an internal com bustion engine whichcomprises, in combination,

a main carburetter including an air intake, a

constant level chamber communicating with said air intake through alarge section passage, an induction pipe to be connected with saidengine, and a throttle valve in said pipe, and an auxiliary carburetterfor starting the engine from cold including a well provided with acalibrated orifice opening into said constant level chamber below thefuel level therein and with only one air inlet in direct communicationexclusively with the space of said constant level chamber above the fuellevel therein, a chamber located below said first mentioned chamber, aconduit starting from said well at a point thereof located below thefuel level in said constant level chamber, passing above said level andopening into one wall of said second mentioned chamber, the upperportion of said conduit being provided with an orifice of small sectionconnecting it with the space of said constant level chamber locatedabove the fuel level therein, a conduit starting from said inductionpipe on the downstream side of said throttle valve and opening into saidwall of the last mentioned chamber, a valve member slidable along saidwall adapted either to connect both of said conduits with said lastmentioned chamber or to cut off both of them therefrom, a conduitprovided with a calibrated orifice for connecting said last mentionedchamber with said air intake, said well of said last mentioned chamberbeing provided with an annular groove surrounding the opening of thefirst mentioned conduit into said wall, and means for connecting saidgroove with said second mentioned chamber.

MARCEL LOUIS MENNESSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS France June 12, 1933

